Fluid-heating furnace



Feb. l2, 1929.,

H.' 'CANNON FLUID HEATING FURNACE Filed may 14, 1924 z sheets-sneu e ik Patented Feb.. 12, 1929.

1,701,837 Em#4 OFFICE.

BIRAM IB. CANNON, F METUCEEN, NEW JERSEY, ASSIGNORTO TE CARBORUNDUM COMPANY, 02E' NIAGARA FALLS, NEW-YORK, A CORPORATION 0F PENNSYLVANIA.

FLUID-HEATING FURNACE.

' appncatio mea may 14,

complished with a considerable reduction of furnace-volume or space over that usually required for equivalent heat capacity; and which will enable the iluid to be heated eiliciently by radiant heat as well as by radiant heat in conjunction with exhaust gases. Further and more speciiic objects and advantages O the invention will appear hereinafter andv will be realized in and through the combinations and arrangements of parts embodied in the claims.

ln the drawings, Fig.. lrepresents'a vertical sectional view through a duid-heating apparatus embodying the invention; and Fig. 2 a transverse sectional view taken through the central portion of the apparatus shown in lFig. 1.

Describing the various parts by reference characters, 1 denotes the shell or envelope oit a furnace, the said shell being formed oi heatresistant material having low heat conductivity, `enabling it to reec't heat without undue absorption thereof. Material suitable for such shell is silocel mortar, magnesia covering, and similar material. The shell is closed at its front end by a head 2 having an opening 3 for the reception ot a wind box ll, whichl fits within the said opening and is provided at its rear end with a sleeve 5. At its rear end, the shell 1 is provided with a stack 6, tor exhaust gases. .j v

The shell 1 is shown as rectangular in'cross section and is provided near the iront and rear ends and near the middle thereof with inwaidly-extending supporting and stabilizing trames or piers 7, the said frames or piers being seated ,within grooves 7 a formed in the top,'bottom, and sides of the shell. 4Between the bottom of each trame or pier and the bottom of the groove provided therefor there extends a supporting metal strap 8, the said strap extending upwardly in and through the side walls of the shell l. i

Projecting through the front ot the wind 19241:.k Serial No. 713,186.

box Il .is a burner nozzle 9, the saidnozzle communicating With a 'l' coupling 1() to which are connected a supply pipe 11, for oil or similar liquid fuel, and a pipe 12 supplying air under pressure for the purpose of atomizing the liquid fuel. vCommunicating with the bottom of the wind box is a pipe 13 tor supplyingA additional or ,secondary air to the wind box. U

rlfhe nozzlev 9 is arranged axially with respect to the sleeve and preferably extends to approximately the rear ofsuch sleeve. rlhis sleeve in turn tits over a neck 14 ormedwith and projecting from a slab 15 which closes the front end of the combustion chamber. This combustion chamber is generally of the type shown in the patent to Hiram iB, Cannon, No. 1,371,774 issued March 15, 1921, and comprises, in addition "to such front wall, a rear wall 16, a bottom wall 17, a top wall'lS, side walls 19, and a Wall intermediate between the top and bottom walls and extending rearwardlytrom above4 the neck 1a to apoint adjacentto but spaced trom the rear wall 16 and forming alower'mixing and cornbustion passage A and an upper mixing and combustion passage B, with aconnecting passage C around the rear end ot the partition wall. Thei top, lbottom and side walls are 'formed ot separate slabs, the side-wall slabs being seated in grooves 17 a and 18a formed in the top and bottom wall slabs respectively.

' The side-wall slabs are provided with seats 19a tor the partition-wall slabs 20. rlhe various parts of which the combustion chamber is" composed are made oli material having great heat-absorbingand radiating qualities. The material whichis preferred to uscior this purpose is silicon carbide or carborundum. lit desired, cement oi like material as' the slabs may be employed at the joints therebetween.

rlhe combustion 'chamber extends from a point closely adjacent to thefront Wall 2 of the casing to a point adjacent tothe rear wall 2l thereof, being supported upon the bottom portions of the 'frames or piers 7 and having' its side walls closely` adjacent to the side portions of said frames. 'i

Bythe construction thus far shownand'described, it will be apparent that the combustion chamber is supported above the bottom of the shell 1 and that it is spaced from the sidesv of such shell, a considerable space being lett between the top of the chamber and the upico per portions of the frames or piers 7. The space within the shell 1 and surrounding the combustion chamber is utilized in a very-edicient manner for the purpose of heating fluid.

Y The fluid to be Aheated is conducted through coils of pipe surrounding the combustion chamber. r21 denotes a supply pipe leading to thecoil, the coil comprising. lengths 22 of tubing extending longitudinali of the shell and connected at their ends by ends 23, as is ordinary in heating apparatus. The tubes 22 are so arranged as to provide an outer series of such t-ubes vsurrounding' the combustion chamber and jointly supported b the frames or piers 7 and theinner wall o the shell l, with an inner series of such pipes also surrounding the combustion chamber and mounted within the frames or piers 7, which frames or piers are also preferably of silicon carbide or carborundum. It will be noted further that the tubes in the inner series are staggered with respect to those in the outer series, this arrangement permitting of a maximum absorption of radiant and reflected heat'by he tubes. vThe iuid heated within the coil is delivered to an outlet pipe 24 leading to a suitable point of use. e' a It will be noted that the passage B is provided with a discharge outlet D located closely adjacent to the front wall l5, wherebyn the products of combustion may pass upwardly and rearwardly in operative relation to the tubes 22 and be delivered to the stack 6.

The apparatus thus far disclosed may be suspendedby the straps 8 oin longitudinal X-beams 25 which are supported on the upper transverse members 26a of supporting frames,

i the vertical members of which are indicated at 26. The upper ends of the metal straps will be looped about the members 25, as indicated at 8a.

In the operation of the ap aratus thus far described oil (or other fluid livered through the nozzle 9 and neck 14 into lthelcombustion passage A, and will burn therein and in the passages C and B. For best results, the combustible fluid and air will be -so controlled thatthe game will travel the full length of the .combustion passages, with the top of the flame at the outlet D. This insures combustion throughout the entireedective length of thecombustion chamber, inaludin the three passa es thereof. As la ree sult, t e chamber will e uniformly heated throughout its extent, enabling it to operate at maximum eliiciency. The adjustment of the. air and fuel tosecure this result will be facilitated by providing the front wall 2 with a mica-covered peep hole located above the outlet D. The combustible mixture within and throuvhout the length of the upper passage B will be heated bythe lower passage IA and the |`partition 20, facilitating 'fthe quick and complete combustion of -themixture in the upper passage B.

to by the` combustion chamber.

el) will be de# The tubes 22 will be heated bythe radiant heat ofthe combustion chamber as well as b tlie products of combustion delivered throug the outlet D but the length of the cbmbustion .chamber and the heat radiating qualities of the same are such that, by the time the` flame has reached the outlet D, complete combustion of the mixture will have been obtained and the temperature of the products delivered to the outlet D will be so reduced that said products may `be discharged directly against the heatabsorbingtubes without injury thereto. By employing material of high heat-absorbing and radiating qualities for the frames or piers 7 the said frames or piers will be quickly heated and willl transfer such heat to the tubes and to the duid therewithin. Furthermore, the employment of a heat-resistant shell or envelope l of low heat conductivity enables the said shell or envelope to reiect, Without great absorption, heat radiated there- The rays of heat directed against this envelope or casing will be reiiected thereby to the tubes and absorbed by the latter. twill be noted that the outer series of tubes 22 is in close proximity to the envelope or casing l,`being partly embedded therein, as indicated; audit will be noted also that this casing is in close proximity to the-bottom and sides fof the combustion chamber, whereby it can operatel with maximum eiiciency in redecting to the tubes the radiant heat directed thereagainst from the combustion chamber. The tubes in the space above the combustion chamber will be heated additionally by convection from the products of combustion as the latter travel from the front of the casing2 to th flue G at the rear thereof.-

Y @wing to the fact thatthe combustion chamber is made of slabs of silicon carbide, it-

bodied in a furnace of the boiler-furnace type, I do not propose to be limited to such particular embodiment.

VAmong the advantages obtained by the apparatus described herein are (a) Complete combustion of the fuel at ver high combustion-capacity.

b) As' muchas 60 percent ofthe total heat resulting from theI combustion of the fuel may be transmitted by radiation to the tubes orother absorbing media.

' (c) The radiant heat ofthe combustion chamber will be uniform throughout the length thereof, thereby eliminating localized Aheating'.

(a) The' sensibieteat of the txhasc gases 1 meneer `Within the radiating vcombustion chamber.

' (g) The arrangement of the combustion chamber and the tubes 22 enables the tubes to constitute an absorbing screen for the radiant heat from the chamber which screen surrounds and substantially encloses the said chamber.

In order to radiate heat efficiently to the tubes or absorbent screen and to the interior of the casing 1', the refractory material of which the combustion chamber is composed should have a thermal conductivity in exy cess of 0.006 cal/cmB/sec/OC.; and, as is Well known, the thermal conductivity of silicon carbide is in excess of that expressed by this formula. Other refractories having av thermal conductivity in excess of that specified are fused aluminum oxide (A12O) and fused magnesium oxide (MgO). c

Having thus described my invention, what l claim is 1. A fluid-heating apparatus comprising an outer casing of heat-resistant and heat-refleeting material, a combustion chamber composed principally of refractory material having a thermal conductivity in excess of 0.006 cal/cmS/sec/OC. mounted Within the said casing, means for heating the said chamber interiorly, and a fluid container interposed between the combustion chamber and the casing and substantially surrounding the former, the said outer casing being arranged in such proximity to the said fluid container and to the said chamber and being composed of such material as to redect eciently to said fluid container heat received by said casing by vradiation from the said chamber.

2. A duid-heating apparatus comprising an outer casing of heat-resistant and heat-reflecting material, a combustion chamber composed principally of refractory material having a thermal conductivity in excess of 0.006 cal /cnis/sec/ OG. mounted` Within the said casing, means for heating the said chamber interiorly, and duid-containing tubes arranged between the said chamber and the said casing and substantially surrounding the former, the said outer casing heilig` arranged in such proximity to the said tubes and to the said chamber and being composed of suchl material as to reflect emciently'to said tubes heat received by said casing by radiation from the said chamber. v

3. A duid-heating apparatus comprising an outer casing of heat-resistant and heat-refleeting material, a combustion chamber having Walls arranged to heat Huid containing tubes and composed principally of refractory material having a thermal conductivity in excess of 0.006 cal/cm3/sec/OC., the said chamber being mounted Within the said casing, means for heating the said chamber interiorly, and fluid containing tubes arranged between the said chamber and the said casing in l5 such position as to be heated efficiently by radiant heat from the said chamber and by heat received by said casing from the said combustion chamber and reflected by said casing to said tubes.

Il. A duid-heating apparatus comprising an outer casing of heat-resistant and heat'refleeting material, piers of heat-absorbent and heat-radiating material mounted Within said casing and projecting inwardly from the inner Wall thereof, a combustion chamber of refractory material having a thermal conductivity in excess of 0.006 cal/cma/sec/OC. exf tending longitudinally of. said casing through andmounted upon said piers, means for heating the said chamber interiorly, and fluid-conltainig tubes interposed between the said chamber and the said casing and mounted in the said piers, the said tubes and the said casing being so arranged with respect to the com- @l5 bustion chamber that the tubes will be heated eciently by heat radiated directly thereto by the combustion chamber as Well as by heat received by said casing from the said combustion chamber and/reflected by said casing to M0 said tubes..

Y 5. :duid-heating apparatus comprising an outer casing of heat-resistant and heat-reflecting material piers composed principally of refractory material having a thermal con'- ma ductivity in excess of 0.006 cal/cm3/sec/00. mounted Within lsaid casing and projecting inwardly fromthe inner Wall thereof, a com-l bastionA chamber composed principally of refractory material having a. thermal conductivity in excess of 0.006 cal/cmS/sec/O-C. extending longitudinally of said casing through.

and mounted upon said piers, means for heat: i

ing the said chamber interiorly, and duidcontaining tubes interposed-between the saidchamber and theV said casing and mounted in the said-piers, the said tubes being arranged in inner and outer series, the tubes in one series being' staggered with respect to those in anotherseries, the said tubes and the said m0 casing being so arranged with respect to the .combustion chamber that the tubes Will be heated eciently by heat radiated directlyj thereto by the combustion chamber as Well as by heat received by said casing from the said casin to said tubes.

6. fluid-heating apparatus comprising` combustion chamber and reflected by said an outer casing,'p 1ers mounted Within said casing and projecting inwardly from the in- -ner wall thereof,a combustion chamber havextending longitudinally of said casingthrough and mounted upon said piers, means for heating the said chamber interiorly, and Huid-containing tubes interposed between the said chamber and the said casing and mounted in the said iers, the said piers being composed principe y of refractory material havmgfa thermal conductivity in excess of 0.006 cal/cms/sec/OC. l

7. A Huid-heating apparatus comprising an outer vcasing of heat-resistant and heat refleeting material, piers mounted within said casing and projecting inwardly from the in-` ner wall thereof, a combustion chamber extendln longitudinally of said casing throng and mounted upon said piers, means -for" heating the'sald chamber interiorly, a

fluid contamer interposed between the said chamber and the said casing, U-shaped straps mounted in the side and bottom walls of the l posed princi allyof silicon carbide mounted v with the sai casing, means for heating the said chamber interiorly, and a fluid container interposed between the "combustion chamber and the casing and substantially surrounding the former, the said outer casing being arranged in such proximity to the said Huid container and to the saidchamber and being composed of such material as to reflect efficiently to said Huid container heat received 'by said casing by radiation from the said chamber. Y

Intestimony whereof, I hereunto ax my signature. d

r' 1- HIRAM B. CANNON. 

